The spectacle frames are generally composed of a front frame or front, on which some lenses are arranged, and some rods or temples, intended to support the frame on the ears of a user.
Firstly, the front generally comprises some rims in which the lenses engage, for which some inner perimeter bezels, of geometry complementary to that of a bezel specific to the lens, are defined to ensure fastening between both elements and maintenance of the position. On the other hand, the front also includes a bridge for joining the rims together and some nose pads, intended to rest on the user's nose.
These frames are made of resistant and low elasticity materials, mainly hard plastic of acetate or metal type, or combinations of said materials, and are intended for permanent mounting of the lenses, it being necessary that any change of lens or of the frame elements is performed by a specialist, in order to avoid deterioration or breakage when disassembling the parts.
Thus, these types of rigid frames do not allow the user to proceed in a simple manner to their assembly and disassembly, and prevent the use of different frames with the same lenses; being therefore necessary that the user has a frame for each set of lenses, with the consequent expense increase.
On the other hand, the connection between the temples and the front is generally produced by a stud and an associated articulation. The articulation axis comprises in general a screw that links together the two parts of a hinge constituting the articulation.
The main issue of said screws is that they are easily loosened with use, being necessary to tighten them frequently to avoid an incorrect position of the spectacles and even the loss of the screw, with the consequent disassembly of the frame. This problem also arises when the temples are intended to be easily interchangeable by the user himself without the need to approach a specialist.